Highly Substituted 2,3-Dihydroisoxazoles by Et<sub>3</sub>N-Catalyzed Tandem Reaction of Electron-Deficient 1,3-Conjugated Enynes with Hydroxylamines
作者:Xiuzhao Yu、Bo Du、Kai Wang、Junliang Zhang
DOI:10.1021/ol100490y
日期:2010.4.16
reaction of electron-deficient 1,3-conjugated enynes with hydroxylamines was developed which provided rapid, metal-free, and regioselective access to highly substituted multifunctionalized 2,3-dihydroisoxazoles under mild conditions. The reactions of 3-(2-arylethynyl)-4H-chromen-4-ones with hydroxylamines afford β-amino enones under the same reaction conditions.
Gold(I)‐Catalyzed Highly Diastereo‐ and Enantioselective Cyclization–[4+3] Annulation Cascades between 2‐(1‐Alkynyl)‐2‐alken‐1‐ones and Anthranils
作者:Rahul Dadabhau Kardile、Tzu‐Hsuan Chao、Mu‐Jeng Cheng、Rai‐Shung Liu
DOI:10.1002/anie.202001854
日期:2020.6.22
This work reports gold‐catalyzed [4+3]‐annulations of 2‐(1‐alkynyl)‐2‐alken‐1‐ones with anthranils to yield epoxybenzoazepine products with excellent exo ‐diastereoselectivity (dr>25:1). The utility of this new gold catalysis is manifested by applicable substrates over a broad scope. More importantly, the enantioselective versions of these [4+3]‐cycloadditions have been developed satisfactorily with
Chemo-selective cross reaction of two enals <i>via</i> carbene-catalyzed dual activation
作者:Xiaolin Peng、Jun Xu、Tingting Li、Yonggui Robin Chi、Zhichao Jin
DOI:10.1039/d0sc03297b
日期:——
play important roles in substrate activation and enantioselectivity control. Many of the possible side reactions are not observed. Our reaction provides highly chemo- and diastereo-selective access to chiral lactones containing functionalizable 1,3-enyn units with excellent enantioselectivities (95 to >99% ee).
An asymmetric epoxidation of electron‐deficient enynes with environmentally benign aqueous hydrogen peroxide as oxidant has been accomplished by developing a chiral N,N′‐dioxide‐Scandium(III) complex catalytic system. In the presence of 0.5–2 mol% catalyst, a variety of trisubstituted alkynyl oxiranes were obtained in high yields (up to 97%) with excellent ee values (up to 99%). Furthermore, control
Exo/endo selectivity-control in Lewis-acid catalyzed tandem heterocyclization/formal [4+3] cycloaddition: synthesis of polyheterocycles from 2-(1-alkynyl)-2-alken-1-ones and 1,3-diphenylisobenzofuran
作者:Hongyin Gao、Xingxing Wu、Junliang Zhang
DOI:10.1039/c0cc02778b
日期:——
tandem heterocyclization/formal [4+3] cycloaddition was developed, which provides rapid, efficient and stereoselective access to highly fused polyheterocycles from readily available 2-(1-alkynyl)-2-alken-1-ones and 1,3-diphenylisobenzofuran under mild conditions.